As per the issue description mentioned, you are receiving an error when trying to save pdf file in Acrobat, is that correct?
Please try following troubleshooting steps:
1- Try saving another pdf file to check if the issue is not specific to this file only.
2- Disable preview pane and details view in Windows Explorer and try again.
3- If the file is on the network, try whitelisting the network path as follow:
Click Edit>Preferences>Security(Enhanced) , choose Add Folder path.
Relaunch Acrobat and try again.
4- Disable Protected View / Enhanced security by clicking Edit menu > Preferences > Security (Enhanced) > select Off under Protected View > uncheck the box next to enhanced security > click OK. Relaunch Acrobat and try again.
Note: Disabling protected view/ Enhanced security is for troubleshooting purpose only, and not recommended. Please turn the feature back on after troubleshooting is complete.
Also, let us know dot version of Acrobat and the operating system installed on the machine? You may refer to the steps given in this link on how to check the version in Acrobat: Identify the product and its version for Acrobat and Reader DC
Let us know if you need any help.